1. Technical Field
An aspect of the present disclosure generally relates to an electronic device, and more particularly to a semiconductor memory device and an operating method thereof.
2. Related Art
Semiconductor devices may be manufactured as integrated circuits. Semiconductor memory devices are data storage devices implemented on the integrated circuit. The semiconductor memory devices are generally classified into volatile memory devices and nonvolatile memory devices.
A non-volatile memory device performs a read/write operation at a relatively low speed, but retains stored data even in the event of loss of power supply. Accordingly, the non-volatile memory device may be used for the task of secondary storage, which does not lose the data when the device is powered down. Examples of the non-volatile memory device may include a read-only memory (ROM), a mask ROM (MROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a phase-change random access memory (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), and the like. Flash memories may be classified into NOR type flash memories and NAND type flash memories.
Like a random access memory (RAM), the flash memories can be written and erased multiple times, and like the ROM, the flash memory can retain its data even when it is powered down. The flash memories are widely used as a storage medium of portable electronic devices such as a digital camera, a smartphone, a personal digital assistant (PDA), and an MP3 player.